The inductor part number inductance code is a free second opinion on the Inductance column. We decoded it on 4,763 Walsin rows: 4,747 agree exactly, 16 do not. Two rows differ by a factor of 1,000, because the part number says microhenry and the Unit cell says nanohenry. Four more carry a value that is on no ladder.
Venatech Limited, an authorised Walsin distributor in Hong Kong, holds the inductor export file published by Walsin Technology (Walsin): 5,410 rows once the QA row Test123999 is removed. We hold no Walsin inductor datasheet, so the file is the only specification we can show you. This post checks the file against itself. A Walsin inductor part number states its inductance, and so does a column, so the two can be compared on every row. Every part number below is real, and every count is one you can repeat.
Can you read the inductance of a Walsin inductor from its part number?
Yes, on 4,763 of the 4,769 rows that carry a nanohenry or microhenry unit. We wrote a decoder and ran it over every row. Three spellings cover everything: 1N5 means 1.5 nH (3,093 rows), 1R5 means 1.5 uH on the power parts and 1.5 nH never (1,536 rows), and a bare three-digit code such as 101 means 100 uH (134 rows). The letter N is the decimal point for nanohenries, R is the decimal point for microhenries, and the third digit of a bare code is a power of ten.
| Layout | Series covered | Rows decoded | Spelling used | Match / mismatch of code against the Inductance and Unit columns |
|---|---|---|---|---|
| Chip, code after the size block | WLCW, WQCW, WLCM, WQCM, WQQC | 1,965 | N or R, e.g. 1N0 |
10 mismatch, all in WQQC, all fractional |
| Chip, code after a style block | WCI, WCA, MCI | 2,154 | N or R, e.g. 56N |
Match on all 2,154 |
| Wirewound and power, hyphen or none | WIP, WPA, WLPH, WQPH, WLFI, WLFW, WFI | 375 | R or three digits |
6 mismatch, across four series |
| Power, hyphen before code | AIP, CSME, CSMEA, CSMM, VEFL, MIP, MAP | 269 | R or three digits |
Match on all 269 |
We counted 4,125 rows tagged nH and 644 tagged uH, 4,769 in all. The other 641 rows are tagged with an ohm unit and are ferrite beads, which we covered in ferrite bead selection. Six of the 4,769 could not be decoded: four beads that sit in the nanohenry group, and two part numbers with a truncated code, CSME0540D-1RN and its CSMEA twin.
How many decodable part numbers agree with the Inductance column?
4,747 of 4,763, which is 99.66 percent. We compared the decoded value with Inductance multiplied by the unit, with a tolerance of half a percent. Sixteen rows fail: 10 by a fractional amount, 4 by a value that is not a step on their own ladder, and 2 by a factor of 1,000. On the other 4,747 the match is exact to the digit printed.
That is a better result than most columns in this export, and we say so deliberately. The failures are few and they are specific. A check this cheap, with an answer this clean, is worth running on any distributor file before it goes into a selector. We parsed all 4,763 rows to get it, and the same method is described for tolerance letters in inductor tolerance code against the tolerance column.
| Failure type | Rows | Series | Example | Match / mismatch |
|---|---|---|---|---|
| Unit conflict, code says uH, cell says nH | 2 | WIP_A | WIP322512A-1R5ML |
Mismatch by 1,000x |
| Value conflict, column not on the ladder | 4 | WLPH, WQPH, WIP, WPA | WLPH201610MR47PP |
Mismatch in value |
| Fractional, column holds a measured-looking value | 10 | WQQC | WQQC0806Z0J12NPB |
Mismatch by up to 2.5 percent |
| Everything else | 4,747 | 22 series | WLCW1005Z0J1N0TB |
Match exactly |
Which two rows are out by a factor of 1,000?
WIP322512A-1R5ML and WIP322512A-3R3ML. The part number says 1.5 uH and 3.3 uH. The Unit cell says nH. We have not seen this counted anywhere: in 4,763 decodable rows, exactly 2 carry a unit that contradicts their own part number, and both sit in the one eight-part WIP_A group.
Read the rest of the group and the unit error is obvious. The other six WIP322512A parts run 0.47, 0.68, 1.0, 2.2, 4.7 and 6.8 uH, with DC resistance rising from 15 to 190 milliohm and rated current falling from 5.8 A to 1.5 A. The two odd rows read 45 milliohm at 3.4 A and 95 milliohm at 2.3 A, which slot exactly between 1.0 and 2.2 uH and between 2.2 and 4.7 uH. They are microhenry parts. Only the Unit cell disagrees.
| Part number | Inductance as published | Unit as published | RDC | Rated current | Match / mismatch against the part number |
|---|---|---|---|---|---|
WIP322512A-1R0ML |
1 | uH | 25 milliohm | 4.9 A | Match |
WIP322512A-1R5ML |
1.5 | nH | 45 milliohm | 3.4 A | Mismatch — code reads 1.5 uH, a factor of 1,000 |
WIP322512A-2R2ML |
2.2 | uH | 60 milliohm | 3 A | Match |
WIP322512A-3R3ML |
3.3 | nH | 95 milliohm | 2.3 A | Mismatch — code reads 3.3 uH, a factor of 1,000 |
Which four rows carry a value that is not on their own ladder?
Four, in two matched pairs. In the 2.0 by 1.6 mm power group, WLPH201610MR47PP and WIP201610P-R47ML both read 4 uH where the part number says 0.47 uH. WQPH201610M1R5PS and WPA201610S-1R5ML both read 2.2 uH where the part number says 1.5 uH. The pairs are different series prefixes carrying identical data, so one wrong cell was copied across.
The ladder test settles which side is wrong. The 201610 WLPH group runs 0.1, 0.24, 0.33, 0.47, 0.68, 1.0, 1.5, 2.2 and 4.7 uH. A value of 4 is not on it. The rated current on the R47 row is 3.5 A at 33 milliohm, between the 0.33 uH row at 4.1 A and the 0.68 uH row at 3.4 A, so the electrical data belongs to 0.47 uH and only the inductance cell is off. The same holds for the 1R5 pair, whose 86 milliohm and 2.4 A sit between the 1.0 and 2.2 uH rows. The 252010 and 252012 versions of the same R47 part read 0.47 correctly.
Why do 10 WQQC rows disagree by a fraction?
Because the WQQC column holds a measured-looking value and the part number holds the nominal. Ten of the 14 WQQC rows at 10 nH and above publish a decimal that the code does not carry: WQQC0806Z0J12NPB reads 12.3 nH, WQQC0908Z0J22NPB reads 21.5 nH. The largest gap is 2.5 percent, inside the plus or minus 5 percent tolerance the same row publishes.
This is not an error in the sense of the other six. It is a different convention in one series of 20 parts. The six WQQC rows below 10 nH, such as WQQC0806Z0J5N5PB at 5.5 nH, agree exactly, which is why the convention is easy to miss. A selector that rounds to the nearest E24 step will place WQQC0806Z0J16NPB, published at 15.7 nH, one step below the 16 nH its part number states. The method that catches it is the same decode, so it is a finding of the check and not an accusation.
What does a filter for 1.5 nH actually return?
32 rows, and one of them is a 3.2 by 2.5 mm power inductor rated 3.4 A. We filtered Inductance equal to 1.5 with unit nH across the whole file. 31 are real chip inductors in 0201, 0402 and 0603 sizes, such as WLCM1005Z0B1N5TB, and the 32nd is WIP322512A-1R5ML. At 3.3 nH the filter returns 62 rows, 61 genuine and the same kind of intruder.
The intruder is cheap to spot once you look and invisible if you do not, because its size column reads 3225 and its thickness 1.1 mm. A radio-frequency designer who sorted by inductance and took the first match in stock would be reading the wrong family of part. The 2.2 uH row WIP322512A-2R2ML has none of this problem, so the error is isolated, which is exactly what makes it dangerous.
What should a cross check do with a row it cannot trust?
State the disagreement, do not resolve it silently. Our free cross-reference tool matches against Walsin’s published catalogue and states every difference from your original, rather than hiding it behind a tick. For these 16 rows the right output is a flagged line that shows the code, the column and the unit side by side, and asks you to confirm.
Paste up to 500 part numbers or drop an Excel or CSV, and read the mismatches before the matches. If your incumbent is from another maker, the same decode applies: write down the inductance the part number states, then compare it with the datasheet value. The power-loss side of the same unit problem is in chip inductor power dissipation, which found 173 rows over 10 W once the units were normalised. The whole line sits on the Walsin inductor page.
What is physically in Hong Kong is on ready stock: 1,125 part numbers as at 23 September 2026, a dated snapshot and not a live feed. Of those, two are inductors and both are in the WLPH series. We hold 28 Walsin datasheets, 451 pages, and none covers an inductor. Ask for the datasheet for your part and you will get it, or a straight answer that no page covers it. We are at Unit 207, 2/F, Sun Ling Plaza, 30 On Kui Street, Fanling, N.T., Hong Kong, (852) 2628 4777.
The short version
A Walsin inductor part number states its inductance, and the code can be decoded on 4,763 of 4,769 nH and uH rows: 3,093 with N, 1,536 with R and 134 with three digits. 4,747 agree with the Inductance column exactly and 16 do not. Two, WIP322512A-1R5ML and WIP322512A-3R3ML, carry the wrong unit by a factor of 1,000. Four, in two twin pairs, carry a value that is not on their own ladder. Ten, all WQQC, carry a value within 2.5 percent of nominal. A filter for 1.5 nH returns one power inductor among 32 rows. We are not calling any of this a product defect, because we hold no datasheet to compare it with. Qualification stays with you, and the check costs one afternoon.
Send us the inductor lines off your bill of materials and we will return the decoded value beside the published one for each. And a question back: if your selector sorts by the Inductance column alone, which of the 16 has it already put on your shortlist?
Frequently asked questions
Can I read inductance from a Walsin inductor part number?
Yes, on 4,763 of 4,769 nanohenry and microhenry rows. The letter N is the decimal point for nanohenries, R is the decimal point for microhenries, and a bare three-digit code means two digits times a power of ten in microhenries. We decoded all of them and 4,747 matched the Inductance column exactly.
How many Walsin inductor rows have a unit that contradicts the part number?
Two. WIP322512A-1R5ML and WIP322512A-3R3ML are tagged nanohenry in the Unit column while their part numbers state 1.5 and 3.3 microhenry, a factor of 1,000. Their resistance and current figures fit microhenry values in the same eight-part group. We found no other unit conflict in 4,763 decodable rows.
Why does WLPH201610MR47PP show 4 microhenry?
The part number says 0.47 microhenry, and the rated current of 3.5 amp at 33 milliohm sits between the 0.33 and 0.68 microhenry rows. A value of 4 is not on that group’s ladder. The WIP201610P-R47ML twin carries the same value, so the cell was probably copied. Confirm against Walsin’s own site.
Why do some WQQC inductors show decimals the part number does not?
Ten of 14 WQQC rows at 10 nanohenry and above publish values such as 12.3 and 21.5 where the part number states 12 and 22. The largest gap is 2.5 percent, inside the plus or minus 5 percent tolerance on the row. It is a different convention, not a 1,000 times error.
Does a filter for 1.5 nanohenry return only chip inductors?
No. It returns 32 rows, and one is WIP322512A-1R5ML, a 3225 power inductor rated 3.4 amp. At 3.3 nanohenry it returns 62 rows, one of them the same kind of intruder. Check the size column and the part prefix before you trust a sorted list.
Does Venatech hold an inductor datasheet to settle these 16 rows?
No. We hold 28 Walsin datasheets, 451 pages, covering 26 MLCC and 2 chip resistor series, and none covers an inductor. Specifications on this line must be confirmed against Walsin’s own site, and we say so for every figure in this post.